HP Pro 4300 C9H70UT C9H70UT#ABA manual Horizontal lines opposite the paper path direction

Table 59. Lines

Possible cause

Recommended action(s)

Vertical lines (in the paper path direction)

The print cartridge is not seated	● Remove the print cartridge and the reinstall it. The top cover
correctly.	should be able to completely close when the print cartridge is
	fully seated.
Defective print cartridge.	● Perform the half self-test functional check. See “Half self-test
	functional check” on page 310. If the defect developed on the
	drum, replace the print cartridge.
Worn or dirty fuser roller.	● Process a printer cleaning page. See “Running the cleaning
	page manually” on page 56. Several pages might be required if
	the fuser is very dirty. If the problem persists, replace the fuser.
	See “Fuser” on page 162.
Static eliminator teeth (just beyond the	● Clean the teeth with a small brush or compressed air. Replace
transfer roller) are contaminated or	the assembly if it is damaged.
defective.
Light is leaking into the printer.	● Make sure that all of the covers are in place. Move the printer
	away from outside facing windows.

Horizontal lines (opposite the paper path direction)

Repetitive defect. If the lines are	● Use the repetitive defect ruler to determine the cause of this
repeated at a consistent interval down	defect. See “Repetitive defects troubleshooting” on page 325.
the page, this is a repetitive defect.
Sharp random lines indicate a problem	● Replace the following in order:
with the laser/scanner control circuitry.	1.	Laser/scanner assembly. See “Laser/scanner assembly” on
		page 173.
	2.	DC controller PCA. See “DC controller PCA” on page 181.
	3.	Cables between the DC controller and the laser/scanner
		assembly.
	4.	Formatter assembly. See “Formatter assembly” on
		page 161.

316 Troubleshooting Q2431-90912